Defroster for a refrigerating system

ABSTRACT

A defroster removes a frost deposited onto an evaporator of a refrigerating system. The defroster is so constructed that an anti-freezing solution preliminarily introduced and cooled within the refrigerating box of the system is sprayed onto the frost to lower the fusing point thereof and the anti-freezing solution diluted by the frost is sprayed onto the heat radiating coil member of the system to cause the water contained in the solution to be evaporated, thus increasing its concentration.

United States Patent [191 Masuda Nov. 20 1973 [54] DEFROSTER FOR AREFRIGERATING 2,526,032 10/1950 La Porte 62/82 SYSTEM 2,672,024 3/1954McGrath.... 62/282 2,747,382 5/1956 Sloan 62/282 [75] Inv nt r: Fu lMasud ,T0ky0. p 2,748,574 6/1956 Gaston 62/282 [73] Assignee: SakuraRefrigerating & Heating Engineering Co., Ltd., Tokyo, Japan PrimaryExaminerWilliam J. Wye [22] Filed: Sept- 1972 Att0meyRobert'D Flynn etal.

[21] A 1. No.: 288 666 pp 57 ABSTRACT 30 Foreign Application priority n;A defroster removes a frost deposited onto an evapo- Mar 21 1972 Japan47/27494 rator of a refrigerating system. The defroster is soconstructed that an anti-freezing solution preliminarily in- 52 U.S. Cl.62/282 62/82 and within the refrigerating box 51 Int. ....:I I F25d21/10 the System is Sprayed the fusmg [58] 6 Field of Search 2/82 282point thereof and the anti-freezing solution diluted by the frost issprayed onto the heat radiating coil mem- [56] R'eerences Cited ber ofthe system to cause the water contained in the solution to beevaporated, thus increasing its concen- UNITED STATES PATENTS nation2,323,511 7/1943 Baker 62/282 3 Claims, 1 Drawing Figure 3 l 7\ fl --u E5}. l4 4 f 21 H n @c "j 16 r "3 O I 5-: 7 37 5 34 DEFROSTER FOR AREFRIGERATING SYSTEM The present invention relates to a defroster,particularly to a defroster for removing a frost deposited onto anevaporator of a refrigerating system.

It is generally known that a refrigeration capacity is lowered due to afrost deposited onto an evaporator such as a fin coil in a refrigerator,freezer etc. in general. There has been heretofore proposed a variety ofdefrosters such as for example a hot-gas type, electric heater typecurrently in use. The conventional defroster, however, can not beoperated during a refrigeration cycle due to a high heat involved.Therefore, in order to attain a defrost it is necessary to stop orinterrupt the refrigeration operation. For this reason a temperaturewithin a refrigerator is increased during the operation of the defrosterby the deenergization of a refrigerating cycle system and/or the heatingoperation of the defroster. Even after resuming the refrigerating cycleit is impossible to lower the temperature within the refrigerator up toa predetermined level unless lapsed for a predetermined period of time.During the time period various inconveniences will also be caused.Furthermore, the refrigeration operation of the refrigerating cyclicsystem is intermittently effected in the prior art refrigerator,resulting in an added operation cost.

The object of the present invention is to provide a defroster capable ofbeing incorporated easily into a refrigerating cycle system and capableof removing a frost deposited during the refrigeration cycle onto theevaporator without stopping or interrupting the refrigeration operationand without using a high temperature which causes some inconveniences inthe refrigeration treatment. I

In the defroster according to the present invention use is positivelymade of the heat of a high-temperature high-pressure gaseous refrigerantcirculating in the high pressure side of a refrigerating cycle system ingeneral. An anti-freezing solution preliminarily introduced and cooledin a refrigerating or cold box for a predetermined period of time issprayed onto a frostdeposited evaporator to cause the frost to lower itsfusing point. Then, the anti-freezing solution diluted by the front issprayed onto the means, through which a high-temperature high-pressuregaseous refrigerant is passed, to cause the water in the dilutedsolution to be evaporated, thus increasing its concentration. The soconcentrated liquid is again used for defrosting.

According to an aspect of the invention there is provided a defrosterfor a refrigerating cycle system having a refrigerating box definging aspace therein, an evaporator for refrigerating said space and a heatradiating member through which a heated refrigerant is passed;comprising a tank for receiving a anti-freezing solution, first meansfor supplying the anti-freezing solution from the tank to the evaporatorso as to lower the fusing point of the frost deposited on the evaporatorto melt the frost, second means for collecting and returnlng to the tankthe anti-freezing solution diluted by the thawed frost, third means forsupplying the antifreezing solution from the tank to the heat radiatingmember to evaporate it for concentration, fourth means for collectingand returning to the tank the concentrated anti-freezing solution, andpre-cooling means mounted in the refrigerating box to cool theantifreezing solution passing through the first means by a coldatmosphere in the space of the box.

FIGURE is a schematic, systematic view showing a defroster according toan embodiment of the present invention.

Explanation is now made of a defroster according to an embodiment of thepresent invention, as applied in a refrigerating cycle system. Since therefrigerating cycle system as shown in the FIGURE may be ofa generallyknown type, explanation is restricted only to the evaporator andcondenser thereof.

in a unit cooler casing 11 provided in the space of a refrigerating box10 there is housed an evaporator 12 consisting of fin coils. Theevaporator 12 constituting one essential element of the knownrefrigerating cycle system is connected through a pipe 13 to the inputterminal of a compressor not shown. Connected through a pipe 15 to theoutput terminal of the compressor is a heat radiating coil 14 as willlater be described.'The coil 14 is connected through a pipe 16 to theinput terminal of a condenser 17. The output terminal of the condensor17 is connected through a pipe 18 to a receiver and then an expansionvalve not shown, and through a pipe 19 to the evaporator.

' A refrigerant performs a predetermined refrigerating function througha cycle including the evaporator, compressor, condenser receiver andexpansion valve as is well known inthe art. I

A defrosting device according to the present invention comprises ananti-freezing solution circulating system.for defrosting, ananti-freezing solution concentrating system and an anti-freezingsolution reservoir tank 20 shared with both the systems.

The anti-freezing solution circulating system includes an inlet pipe 22having one end connected to the tank 20 and the other end thereofextending within the casing 11 to introduce the anti-freezing solutionin to the casing from the tank 20 under the pumping action of a pump 21.Situated above the evaporator coil 12 within the casing 11 is theextended end of the pipe 22 whichspraysthe anti-freezing solutionthrough its no:- zle 23 onto a frost layer deposited on the fin coil.Below the coil 12 there is provided a funnel-like tray 24 for collectingthe sprayed solution containing the water melted from'the frost. To theoutlet of the tray 24 is connected one end of an outlet pipe 25 theother end of which 'is connected to the tank 20. The arrangement permitsthe anti-freezing solution collected within the tray to be returned tothe tank.

At the inlet pipe 22 there areprovided a pre-cooler 27, manuallyoperating valve. 37 and check valve 36 for sending, for a predeterminedtime period, a controlled amount of pre-cooled anti-freezing solutiononto the evaporator. The pre-cooler' 27 is disposed at the corner in thespace of the refrigerating box 10 to give not so much affect to therefrigeration effect, and the antifreezing solution is cooled by a lowertemperature atmosphere within-the refrigerator. The pre-cooler 27 maytake a variety of forms but, as a preferable form, use is made of bentrectangular pipes arranged one over the other at a multi-stepped,spaced-apart relation to raise a cooling effect with a smaller spaceoccupied. The anti-freezing solution led through check valve 36 from thetank 20 is sent to the pre-cooler 27 where it is held and pre-cooled fora predetermined period of time. The pre-cooled liquid, as required, issupplied at a desired flow amount onto the evaporator 12 through a checkvalve 36.

In the embodiment according to the present invention, to assist thecooling function of the pre-cooler 27 the inlet and outlet pipes 22 and25 are associated with each other outside the refrigerator to constitutea heat exchanger 26. The heat exchanger 26 functions to cool thatanti-freezing solution passing through the inlet pipe 22 raised to arelatively high temperature for the reasons set out below by thatrelatively lowtemperature anti-freezing solution passing through theoutlet pipe 25 thereby precool the former solution before entry into apre-cooler 27. The heat transfer, for example, may be formed by eitherarranging the portions of the inlet pipe and outlet pipe at a coaxialarray, or spirally winding the portion of the outlet pipe around theportion of the inlet pipe. Since the anti-freezing solution issufficiently cooled by these two cooling mechanisms 26, 27 before beingsprayed onto the evaporator 12, it will be understood that norefrigeration capability will be lowered, even if the anti-freezingsolution is sprayed onto the evaporator.

Disposed above the nozzle 23 in the unit cooler casing 11 is aneliminator 28 for preventing an escape from the casing 11 of theanti-freezing solution sprayed from the nozzle 23. Also located abovethe eliminator 28 is a blower 29 for generating an upward directing airstream within the casing 11 to enhance a defrosting effeet.

The anti-freezing solution concentrating circulation system includes aconcentrator 30, in which the heat radiating coil 14 is contained, andan inlet pipe 32 for introducing, under the action of a pump 31, theantifreezing solution from the tank into the concentrator 30. Mounted atthe end of the inlet pipe 32 and within the concentrator is a nozzle 33which is situated above the coil 14. Through the nozzle 33 theantifreezing solution from the tank 20 is sprayed onto the heatradiating coil 14. This will cause some water contained in the sprayedsolution to be evaporated since the high-temperature refrigerant ispassed through the heat radiating coil 14. From this it will beunderstood that during the spraying the anti-freezing solution will beconcentrated. Arranged below the radiating coil 14 within theconcentrator is a funnel-like tray 34 for collecting the so-concentratedanti-freezing solution. The outlet of the tray 34 is connected to thereservoir tank 20 through an outlet pipe 35. As a result theconcentrated anti-freezing solution is returned to the tank.

Within the concentrator 3( an eliminator 40 is provided to trap dropletsof the anti-freezing solution thereon, thereby preventing thedissipation of the solution. As a result only water vapor can be passedupwardly. Below the coil 14 there is disposed a blower for facilitatingheat dissipation of the coil 14.

On the tank 20, for example, a liquid-level measuring device 38 offloating type is provided for measuring the liquid level of theanti-freezing solution within the tank.

This device is connected to a switch means 39 for selectively drivingthe pump 31. As a result when the antifreezing solution within the tank20 is reached at more than a predetermined level, i.e., the solution hasits concentration reduced the pump 31 automatically starts its operationto get the concentration system into warks.

Let us now explain the refrigeration cycle of the defroster according tothe present invention, i.e., the aspect of sending to the condenser 17 ahigh-temperature and high-pressure gaseous refrigerant caused by thecompressor and the aspect of cooling the inside of the refrigerating box10 through evaporation of the liquefied refrigerant in the evaporatorcoil 12.

The anti-freezing solution within the tank 20 is raised to a fairlyhigh-temperature through the concentrating circulation system which isthen sent through the heat exchanger 26 to the pre-cooler 27 where it isprecooled for a predetermined period of time. Then it is sent to thenozzle 23, through which it is sprayed onto the coil 12 to cause thefrost deposited thereon to be thawed. The anti-freezing solution dilutedby the thawed water is collected in the tray 24 and sent back to thetank 20 by way of the pipe 25. In this case the anti-freezing solutionso returned to the tank is diluted and extended by the thawed water.However, according to the present invention the diluted solution isconcentrated through the concentration cycle to maintain at all timesconstant the concentration of the anti-freezing solution within thetank. That is, the anti-freezing solution within the tank is sprayedonto the radiator coil 14 through which the high-temperature refrigerantis passed so that the diluted anti-freezing solution is evaporated tocause it to be concentrated. The soconcentrated high-temperatureanti-freezing solution is collected in the tray 34 and then returned tothe tank 20, where it is mixed with the diluted anti-freezing solutionfrom the defrosting cycle. Thus, the concentration of the solutionwithin the tank 20 is maintained constant.

The defrosting circulation system of the defroster according to thepresent invention may be operated either continuously during theoperation of the refrigeration cycle, or intermittently by means of atimer etc. Otherwise the defrosting circulation system of the defrostermay be operated only for a predetermined period of time, taking intoconsideration the extent to which a frost is deposited onto the coil 12.Though as the concentration means diluting anti-freezing solution theheat radiating coil is used in the present embodiment, the other means,such as for example a condenser, through which a high-temperaturegaseous refrigerant is passed, may be used.

What is claimed is:

l. A defroster for a refrigerating cycle system having a refrigeratingbox defining a space therein, an evaporator for refrigerating said spaceand a heat radiating member through which a heated refrigerant ispassed; comprising a tank for receiving an anti-freezing solu' tion,first means for supplying the anti-freezing solution from the tank tothe evaporator so as to lower the fusing point of the frost deposited onthe evaporator to melt the frost, second means for collecting andreturning to the tank the anti-freezing solution diluted by the thawedfrost, third means for supplying the antifreezing solution from the tankto the heat radiating member to evaporate it for concentration, fourthmeans for collecting and returning to the tank the concentratedantifreezing solution, and pre-cooling means mounted in therefrigerating box to cool the antifreezing solution passing through thefirst means by a cold atmosphere in the space of the box.

2. A defroster according to claim 1, further including a heat exchangerconstituted by the parts of the first and second means to cool theanti-freezing solution in switch means connected to the device tooperate the third means when the anti-freezing solution in the tank isreached at more than a predetermined level.

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N 7 3Dated November Inventor(s) j'iO MASUDA It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

In the Abstract:

line 1 change "removes" to --for removing- V line 2, after "systems"delete The defroster";

Column 1 line 3 after "defroster," insert and more--;

line 4, delete "a" (second occurrence) lines 6 and 7, delete "a" line10, after "type," insert and an--; I line 13 delete "a" 1 insert --the-;

"line 15, after reason" delete "a" and insert the-;

, line 21 delete "up" lines 21 and 22, delete "unless lapsed for apredetermined" and insert in a short; line 22, after "During" change"the" to --this--; a line 26, after "resulting in" delete "an" line .31after "removing" delete a" between lines 36 and 37 insert the headingSummary of the Inventionline 46, after "means" delete line 53, ehange"definging" to defining line 55, after "passed" delete insert line 56,delete "comprising" insert I'he defroster comprises--; change "a" (lastoccurrence) to --an-;

FoRM PO-1050 (10-69) USCOMWDC l-Ls. GOVEINMIkT PIINTIHG OFFICE II.oP'all'lal,

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,772,897 Dated November 20,- 1973 Inventor(s) F ji-0 'MASUDA I It'iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

. a Column 2, between lines 2 and 3 insertthe heading Brief Descriptionof the Drawingline 3, change "FIGURE" to The single Figure--; betweenlines 5 and 6 insert the heading ---De'tailed Description of theDrawing--; line 1 2, after "space" change "of" to' -within--; line 14,change "consisting of" to --including--; line 50, after "tray" insert--24- f linef52, change "operating" to --operated-; line 62, after"other" change at to inline 63 after "raise" change "a" to '--the---;last line, change "at" to -with-;

Column 3, line 1,. after "desired" insert amount of--;

after "flow" delete "amount" line' 2, change "a" to -the; I line 12,after-"pipe 25" insert --to-; linefIS, after "outletp'ipe"-'change,"a't" to --in-; line 20, change "no" to the--; line 21after "will" insert -'-'not-; I line 24, after "preventing" change- "an"to -the-- line 27, change "upward directing" to upwardly directed-; line28, change "a" to the--; line 58, change "floating" to th float--; line62, delete "is reached at more""and insert reaches a level higher--;

FORM Po-1oso (10-69) USCOMM DC 603764 69 U.. GOVERNMENT PRINTING OFFICEI9" 0-Jl-ISL UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 3 772 897 Dgt d November 20', 1 973 Inventor(s) Fuj i0 MASUDAIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below;

Column 3', line 64, after reduced' insert line 65, change "get" to--start--; line 66, change "warks" to --operationline 67, delete "Let usnow explain" and insert -There will now be explained-;

Column 4,; line 4, change lique--"v to -.-li-qui v "lines 19 and 20,delete "at all times constant" line 21 after "the tank" insert -constantat' all timeS- I I line 27, change 'tray 34" to -tray 24-; li ne 40,"vafter "which" delete "a" ;'c hange "onto" to --on--; delete "Though"insert -"-While a heat radiating coil is-used--; line 42, delete "theheat radiating coil is used" 7 line 43 before "other" delete the line59, delete "concentration" insert concentrating the .antifreezingsolutionline 66, change "constituted by" to -.-'-comprised- Column 5,line 4 change "has" to --j 1 Column 6, last line; delete is reached atQre" insert -reaches a level higher--;

Signed and sealed this th day of June 197M,

(SEAL) Attest:

EDWARD MJLETCERJR. I T CrMARSHALLDANN Attestina; Officer Y Commissionerof Patents F RM -105O (10-69) USCOMM DC 60310 P69 I I i U. S.GOVEIIIMENT PRINTING OFflE I95, O-QlC-SSL

1. A defroster for a refrigerating cycle system having a refrigeratingbox defining a space therein, an evaporator for refrigerating said spaceand a heat radiating member through which a heated refrigerant ispassed; comprising a tank for receiving an anti-freezing solution, firstmeans for supplying the anti-freezing solution from the tank to theevaporator so as to lower the fusing point of the frost deposited on theevaporator to melt the frost, second means for collecting and returningto the tank the anti-freezing solution diluted by the thawed frost,third means for supplying the anti-freezing solution from the tank tothe heat radiating member to evaporate it for concentration, fourthmeans for collecting and returning to the tank the concentratedantifreezing solution, and precooling means mounted in the refrigeratingbox to cool the antifreezing solution passing through the first means bya cold atmosphere in the space of the box.
 2. A defroster according toclaim 1, further including a heat exchanger constituted by the parts ofthe first and second means to cool the anti-freezing solution in thefirst means by the anti-freezing solution in the second means.
 3. Adefroster according to claim 1 wherein said tank has a device measuringthe liquid level in the tank and switch means connected to the device tooperate the third means when the anti-freezing solution in the tank isreached at more than a predetermined level.